1. Field
Illustrative aspects of the invention relate to telephone apparatuses.
2. Description of the Related Art
Telephone apparatuses including a base unit connected to an external line and at least one cordless handset configured to perform wireless communication with the base unit have been available.
Normally, such telephone apparatuses are configured to establish a so-called “two-party call”, which is 1) a call between an external communication apparatus connected to the external line (another telephone apparatus connected to the external line) and a base unit, 2) a call between the external communication apparatus and a cordless handset in which the base unit is not party to the call, but functions as a relay, or 3) a call between the base unit and the cordless handset.
A telephone apparatus configured to establish a three-party call among an external communication apparatus, a base unit, and a cordless handset is described in Japanese Unexamined Patent Application Publication No. 2004-96385.
The telephone apparatus described in Japanese Unexamined Patent Application Publication No. 2004-96385 has a function of allowing manual change of a two-party call into a three-party call and a function of allowing automatic change of a two-party call into a three-party call.
When changing a two-party call between an external communication apparatus and a base unit into a three-party call by adding a cordless handset to the two-party call, the three-party call can be established manually by pressing a cordless-handset button in an operating part of the base unit to call the cordless handset. When changing a two-party call between an external communication apparatus and a cordless handset into a three-party call by adding a base unit to the two-party call, the three-party call can be established by pressing a base-unit button in an operating part of the cordless handset to call the base unit.
In contrast, in a system with the function of allowing automatic change of a two-party call into a three-party call, the telephone apparatus has a three-party call mode in which a three-party call is established (hereinafter, referred to as a simple relay mode). Where a user sets the three-party call mode at a base unit or at a cordless handset in advance, the three-party call is permitted to be established for an incoming call at the respective base unit or cordless handset without requiring an operation using the operating part. That is, if the three-party call is permitted and a user activates the other of the cordless handset or base unit during a two-party call between the external communication apparatus and the respective base unit or cordless handset, then a three-party call is automatically established.
However, for the telephone apparatus disclosed in Japanese Unexamined Patent Application Publication No. 2004-96385, in a case where the simple relay mode is set in advance, the telephone apparatus unconditionally establishes a three-party call. As a result, the user cannot individually decide whether to establish a call with the device calling the user's device (i.e., the base unit or cordless handset) during a two-party call.
In contrast, in a case where a user wishes to conduct a three-party call when the simple relay mode is not activated, the user must manually set the simple relay mode or must operate an operating button provided on a base unit or a cordless handset.